Vulcanization of Rubber Compounds

1940 ◽  
Vol 13 (4) ◽  
pp. 918-925 ◽  
Author(s):  
E. W. Booth ◽  
D. J. Beaver

Abstract 1. Rubber dissolves approximately one per cent of hydrogen sulfide when saturated at room temperature. 2. All types of commercial accelerators are retarded in rate of vulcanization as a result of treatment with hydrogen sulfide, and the retardation is directly proportional to the hydrogen sulfide content. 3. The physical properties of mercaptobenzothiazole types of accelerators and diphenylguanidine are not permanently affected by hydrogen sulfide, but dithiocarbamates, thiuram sulfides, aldehydeamines and litharge are permanently affected. 4. Rubber compounds containing mercaptobenzothiazole types of accelerators or diphenylguanidine, which have been treated with hydrogen sulfide and then degassed in a vacuum oven, show normal rate of vulcanization. Compounds containing aldehydeamines, litharge or carbon black show permanent retarding, even after degassing. 5. Increased zinc oxide or sulfur has no appreciable effect on the retardation. 6. Little or no zinc sulfide is formed as a result of treatment with hydrogen sulfide. 7. Hydrogen sulfide treatment of rubber compounds retards the rate of combination of sulfur with rubber. 8. In no case did hydrogen sulfide treatment improve the physical properties of the vulcanizate.

1931 ◽  
Vol 4 (2) ◽  
pp. 248-255
Author(s):  
D. J. Beaver ◽  
J. W. MacKay

Abstract Mixtures of varying ratios of either channel black or a soft carbon black with whiting, lithopone, or clay show additive physical properties. Mixtures of soft carbon with zinc oxide also show additive properties, while mixtures of channel black and zinc oxide show poorer resistance to abrasion, higher modulus, and higher tensile strength than would be shown by purely additive mixtures. The explanation of these results appears to be found in the chemical reaction between the basic zinc oxide and the acidic compounds in the rubber or on the black. These results have been applied to the formulation of a solid-tire stock which will give a better resistance to abrasion and blow-out when using a soft black than when using a channel black.


1928 ◽  
Vol 1 (3) ◽  
pp. 458-464
Author(s):  
D. J. Beaver ◽  
T. P. Keller

Abstract The data presented herein show that in general the presence of oxygen on carbon black retards the rate of vulcanization in direct proportion to the amount of oxygen present and also decreases the maximum physical properties obtainable with a given amount of accelerator. The aging data show that the presence of this oxygen on the black increases the rate of aging as the amount of oxygen increases, but not in direct proportion to the per cent of this oxygen present. It can be concluded, therefore, that compounds which contain a small amount of oxygen, such as thermatomic, G black, or acetylene black, will give better aging stocks than compounds containing higher amounts of oxygen such as lampblack and standard channel blacks. No correlation could be found between the acetone extract, iodine adsorption, or oil adsorption, and the effect of these blacks on the rate of cure or aging.


2021 ◽  
Vol 66 (7) ◽  
pp. 396-400
Author(s):  
Irina Gennadievna Popova ◽  
O. G. Sitnikova ◽  
S. B. Nazarov ◽  
R. I. Sadov ◽  
I. A. Panova ◽  
...  

We examined 70 women who were 22-40 weeks pregnant and their newborns. Of these, 15 women with moderate PE made up group 1, 22 women with severe PE-group 2, and 55 women with uncomplicated pregnancy without hypertensive disorders - the control group. Blood was collected from women when they were admitted to the clinic, and blood was taken from newborns for 3-5 days of life. The concentration of hydrogen sulfide was determined by the method of K. Qu et al [17]. There was a decrease in the level of hydrogen sulfide in the blood serum of women whose pregnancy was complicated by severe preeclampsia. In newborns born to mothers with preeclampsia, an increase in the concentration of hydrogen sulfide was detected in the blood, which is probably a compensatory reaction aimed at restoring vascular homeostasis during early postnatal adaptation.


2014 ◽  
Vol 962-965 ◽  
pp. 736-740
Author(s):  
Feng Yan

This project carries out the research on influence factors of wells producing hydrogen sulfide in connection with the actual situation of producing hydrogen sulfide in Qi-40 steam drive process. Experimental studies have shown that: A. temperature is the main external factors of produce hydrogen sulfide, It will produce hydrogen sulfide when temperature is above 100°C, hydrogen sulfide content increase about 300ppm in average when the temperature increase per 20°C; hydrogen sulfide content will be in the greatest increase when temperature at the range of 160°C~180°C; the rate of increase in the levels of hydrogen sulfide will significantly reduce when temperature above 180 °C.B. Adding Chemical agent with surface activity can inhibit the release of hydrogen sulfide. C. Adding acid chemical agent will make the content of hydrogen sulfide increase. The experimental study also investigated hydrogen sulfide prevention measures.


2021 ◽  
Author(s):  
OV Boiko ◽  
YuI Dotsenko

The current measures for protection of the gas processing plant employees cannot fully prevent the impact of pollutants. Evaluation of the immune system is one of the methods for monitoring of the employees' health, and testing the system of measures used to improve the working conditions. The study was aimed to identify alterations in the immune status of the employees at the gas processing and high hydrogen sulfide content condensate processing facility depending on their working experience. The working environment and the employees' immune system were evaluated by standard methods. Pollutants were detected with the Bruel & Kjaer 1302 Multi-Gas Monitor, and the Tsvet-550 gas chromatographer. A total of 160 employees and 81 controls (blood donors of the regional blood transfusion station) were surveyed. The immune system was evaluated using the System 9000 Plus hematological analyser, Cyto FLEX LX flow cytometer, UNICO 2100UV specrophotometer, and KFK-3-03-ZОМЗ photometer. It was concluded that the existing complex of occupational and industrial hazards affects the immune status of the main production unit employees, which is reflected in the decreased CD20 levels and increased CD8 levels along with the constant levels of CD4. Correlations were revealed between the immuniglobuline level alterations, decrease in the phagocytic index and phagocytic number, as well in lysozyme activity, and the working experience. Pollutant exposure results in altered immunity of the employees, which could be considered the adaptation mechanism.


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